5 Reasons Why Your Toilet Is Leaking at the Base

Becca Stokes
Written by Becca Stokes
Reviewed by Joseph Wood
Updated March 3, 2022
The interior of a clean and modern bathroom
Photo: Pixel-Shot / Adobe Stock


  • The most likely culprits are the drain line, wax ring, flange bolts, cracks, or water supply line.

  • You can replace a wax ring on a toilet, or you can call in a pro for the job.

  • A pro may recommend replacing parts or the entire toilet.

  • Leaks can lead to expensive water bills and repairs, so quickly investigate.

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Are you noticing water pooling up around your toilet while you’re draining your bubble bath? Or maybe you found a puddle of water around your toilet for no apparent reason. Toilets can leak from the tank, cracks in the bowl, the water supply line, or the base. Here are five reasons why your toilet may be leaking from the base and what to do about it.

1. Clogged Drain Line

If water is leaking from the base of your toilet and the toilet is clogging easily, you may have a clogged drain line. The drain line is responsible for moving the flushed water out of the home. 

A clogged drain line can put pressure on the wax ring at the base of your toilet, which can break the ring and cause toilet leaks. If you suspect this is the problem, contact a plumber for an evaluation. They can unclog the drain line and get your toilet back up and running in no time. 

2. Old Wax Ring

Wax rings on toilets, as their name may indicate, are made of wax. That’s because wax is the ideal material for the job: it’s easy to mold and shape into exactly the right configuration to prevent water from leaking out of the base of your toilet. 

Unfortunately, another thing wax is known for is being delicate. If the wax ring at the base of your toilet is loose, it can’t prevent water from leaking out of the base and needs to be replaced. If you are a confident DIYer, you can replace the wax ring yourself

If you prefer to let a pro handle it, call a plumber in your area to install a new wax ring. The cost for a pro to repair a base leak in a toilet is $240 on average, depending on location. Some plumbing pros will charge an hourly rate of between $75 and $150 an hour to get the job done.

3. Loose Flange Bolts or Floor Flange

A luxury bathroom with a wooden vanity and a white toilet bowl
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The floor flange bolts have one critical job: keeping your toilet secured to the ground. If you notice your toilet is rocking or loose, it may mean you have loose flange bolts that could spring a leak. 

All you need is a good pair of pliers or a crescent wrench. Take off the plastic caps on the bottom of the toilet, and twist the bolts in a clockwise position until they’re nice and firmly in place. Flange bolts that cannot be tightened might need some oil, or you may need to replace them. If they seem to spin forever, they may have fallen out of their "track" on the flange, or the flange itself may be broken.

If you find that the flange is broken, it’s time for a new one. The average cost to replace a toilet flange is about $145 to $165 but can reach $600 in more urban areas of the country. 

4. Cracked Toilet Bowl 

Toilet bowls are sturdy, but accidents can happen, and toilet bowls sometimes crack. Usually, the hairline cracks are on the surface—but if they go deep enough—they can lead to leaks at the base. 

Replacing a toilet bowl costs between $70 and $100, not including labor. Many plumbers will suggest that you replace the entire unit rather than just the bowl if the crack is wider than one-sixteenth of an inch. Replacing the entire toilet costs about $220 to $530. A hidden leak in your bathroom can increase your monthly water bill and cause water damage to your floors, so if you find a toilet leak don’t delay in resolving the issue. 

If you’re considering a new toilet bowl, Joseph Wood, Expert Review Board member, Master Plumber, and Founder of Boston Standard Company suggests upgrading to a High-Efficiency Toilet (HET). “If your toilet happens to be sky-blue, avocado, or pink in color (common colors in old, outdated toilets), you can likely save up to 25,000 gallons of water by going to a new HET. For the amount of time that a toilet lasts, all new models should be HET, comfort height, and include a soft-close seat as these are the modern standards for living.”

5. Leaking Water Supply Line 

Water can collect at the base of the toilet due to a leaking water supply line, the hose that runs from the bottom of the toilet tank to the water supply valve on the wall or floor. 

Turn off the water by twisting the valve on the water supply (either on the wall or the floor). Using a wrench, gently tighten the nut on the hose (where it connects to the tank) and the nut on the valve. Turn the water back on, flush the toilet, and check for leaks. 

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